1. Field of the Invention
The present invention relates to a touch input pen, especially to an electromagnetic touch input pen having a USB interface.
2. Description of the Related Art
As is known, a touch module, if placed over a display panel, has to be implemented with transparent materials like glass and ITO (Indium Tin Oxside), so as not to hinder the display of the display panel. However, if the display panel is an electrophoretic one—utilizing surrounding lighting for illumination, then the illumination attenuation caused by the touch module can still degrade the display brightness, even though the touch module is made of transparent materials. As such, the electrophoretic display panel is placed in general over the touch module.
Besides, to avoid damaging the display panel which overlies the touch module, when performing touch input, non-contact mechanism such as magnetic touch sensing mechanism is commonly utilized for the touch module. The magnetic touch sensing mechanism demands a digital input pen which is generally powered by rechargeable batteries. When the battery power of the digital input pen is exhausted, a charger is then needed to charge up the rechargeable batteries. Please refer to FIG. 1, which is a perspective view illustrating an appearance of a prior art digital input pen being charged by a specific charger. As illustrated in FIG. 1, a digital input pen 100 is placed on a charger 110 to have its rechargeable batteries charged. However, using the charger 110 to charge the rechargeable batteries inside the digital input pen 100 has a disadvantage—the user has to carry the charger 110 with him/her, otherwise the rechargeable batteries can not get charged.
To overcome the mentioned disadvantage of charging a digital input pen with a specific charger, the present invention proposes a novel electromagnetic touch input pen, which can access a DC power via a USB interface to charge the rechargeable batteries.